Pharmacological activities of 3, 3-diphenyl-3-hydroxypropionic acid diethylaminoethyl ester hydrochloride (DPE-HCl) and its three quaternary ammonium salts (DPE-methyl iodide, DPE-ethyl iodide, and DPE-ethyl bromide) were investigated and following results were obtained. Intravenous LD50s in male mice were 25.5 mg/kg for DPE-HCl and 12.5 mg/kg for quarternary ammonium salts. The topical anesthesic action of DPE-HCl to rabbit cornea was assumed to be almost the same as lidocaine, while there was no such activity in the quaternary ammonium salts. The spontaneous movement of dog ileum was decreased by these compounds, and the intensity of this action in quaternary ammonium salts was stronger than DPE-HCl. These compounds did not affect the respiration of a dog markedly. DPE-HCl showed a transitory hypotensive action on the blood presesure of a dog, but the quaternary ammonium salts caused a marked and sustained fall in blood pressure.
